Antennas



Jan. 28, 1958 s, ucc 2,821,709

ANTENNAS Filed March 21, 1952 I -l IS F 2! l I Z L. r 35/ .3 l M 1, l5-i I i INVENTOR. I SALVATORE Fuccl H/s HTTORNEYs ANTENNAS SalvatoreFucci, New London, Conn.

Application March 21, 1952, Serial No. 277,889

7 Claims. (Cl. 343-793) (Granted under Title 35, U. S. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates to improvements in antennas, and moreparticularly pertains to improvements in very high and ultra highfrequency around-the-mast antennas.

Antennas constructed for use on surface craft, aircraft or landinstallations, and conventional submarine antennas, are not sufficientlypressureproof and do not meet the minimum requirements of structuralrigidity that are desired of an antenna employed in submarineoperations. Multiple antennas heretofore installed on submarinesemployed an insulator to separate the upper and lower radiatingelements, but such an insulator subjects the device to the seriousdisadvantages of weakening the antenna mechanically and complicatinginordinately the problem of pressureproofing. In such antennas, the solesupport for the upper radiating section of the antenna is the innerconductor of the transmission line, which extends through the insulator.In such structure, extension of the antenna mast is not feasible, andmultiple antenna arrays cannot be provided conveniently.

The subject device overcomes the foregoing disadvantages of the priorstructures and provides a pressureproof, structurally rigid multipleradiator adapted for use on extensible submarine antenna masts. Theseresults are accomplished by substituting a quarter-wave isolatingsection between the upper and lower radiating elements for the insulatorheretofore employed, such section also serving to compensate for thereactive component of the antenna and to assist in extending thefrequency range of a single unit; by the folding back of the upperradiating element to form another quarter-wave section that isolatesthis upper radiating element electrically from the extended mast, thuspermitting the stacking of additional antennas on the single mast; andby feeding the antenna 01f center by means of a separate cable, therebyeliminating the need of breaking the mast at the center.

The principal object of this invention is to provide an around-the-mastantenna that meets the pressureproofing and structural rigidity optimumrequirements of extensible multiple-stack submarine antenna.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

Fig. 1 is a fragmentary longitudinal cross section of an around-the-mastantenna, showing a preferred embodiment of the invention;

Similar numerals refer to similar parts throughout the several views.

The antenna is supported on a retractable mast 11,

Fig. 2 is a section taken on the line 2-2 of Fig. l;

nited States Patent I assists Patented Jan. 23, 1958 which is a cylinderadapted to receive telescopically a cylinder 13 of smaller diameter,part of said cylinder 13 extending beyond the end of the mast l1.

A tubular radiator 15 is formed as an invertedor ope bottomed cup andthe conductive closed end 17 of said cup is secured to the cylinder 13in any suitable manner. Said closed end 17 is provided with a firstsmall bore or aperture 19 through which a first coaxial conductor 21 ispassed, and a second small bore or aperture 23 through which a secondcoaxial conductor 25 is passed. A second tubular radiator 27 is securedto the cylinder 13 in any suitable manner, such as by means ofconductive mounting ring 29. Said radiator 27 is isolated from cylinder13 by means of a quarter wavelength section of coaxial transmission lineformed by the portion 31 of the outer surface of the cylinder.13projecting above the closed end 17 and the inner surface 33 of thecoaxially disposed portion of the radiator 27.

The radiator 27 has a folded back portion 35 that serves as a radiatingelement. A second quarter wavelength isolating section is formed by thecoaxial line section comprising the inner surface 37 of the folded backportion 35 and the outer surface 39 of the coaxially disposed portion ofthe radiator 27, thereby insuringthat no radiation from the radiator 27spills over around the edge of said radiator.

Direct off-center feed is accomplished by connecting the inner conductor41 of the coaxial cable 21 at a point on the junction of the folded backportion 35 and the coaxially disposed portion of radiator 2'7. The outerconductor of cable 21 is connected to the radiator at the closed end 17,as shown in Fig. I. Said cable 21 is secured upon cylinder 13.

A similar antenna can be mounted on the cylinder 13 and disposedvertically above the radiator hereinbefore described. Suchsuperstructure can be of the same construction as the antenna describedhereinabove, except that it is preferably scaled down in physicaldimensions to be resonant at a desired higher frequency. Such similarantenna is fed through conductor 25. The elements of such superstructureare designated in the drawing by the reference numerals of theircorresponding elements in the radiator described hereinabove, but withthe subscript a added to each such designation.

It is apparent that as many such radiators as are desired can be mountedas above described in superposed relation. For example, still anothercylinder 13b for mounting a third antenna can be secured by means of themounting ring 29a. It is also apparent that the radiating sections canbe conical, or can have other shapes suited to the production of desiredfrequency characteristics, and that other geometric configurations toproduce directionality can be employed in lieu of the describedstructure that provides a substantially omnidirectional radiationpattern. Since the antenna described requires no insulation to beintroduced at any point in its construction, very high structuralstrength can be achieved and pressureproofing is facile in view of thefact that only the end seals of the external feed cables need to bepressureproofed.

Obviously many modifications and variations of the present invention arepossible in the light of the teachings. It is therefore to be understoodthat within the scope of the appended claims the invention may bepracticed otherwise than as specifically described.

I claim:

1. An ultra-high-frequency antenna for a high-frequency energytransducer comprising a support, a first tubular radiator mounted onsaid support,--.afs e ond.ta-

each radiator to said support, high-frequency isolating means betweensaid support and one of said radiators, and transmission line meansconnecting said radiators to such transducer.

2. The antenna as defined in claim 1, wherein, said sup; port iscoaxially disposed relative said first and second radiators. i i i h a tna a ie rl n a m h ei a d t an mission line means comprise a coaxialconductor having, an inner conductor connected toone of said radiatorsand,

an outer conductor connected to the other radiator, said coaxialconductor being secured on said support.

4. An ultra-high-frequency antenna system for a highfrequencyenergy'transducer comprising a stacked coaxial arrangement of tubularradiators, pairs of said radiators being adapted to be energized atfrequencies oi operation diflerent from that of other pairs,transmission, means coupled to said radiators, aconirnon supportdisposed coaxi'ally with respect to said radiators, said radiators beingmounted in vertical alignmenn onfsaid support, and. conducti've elementscoupling similarly disposed ends of each of said radiators to saidsupport.

5 Thesystem as defined in claim, 4 further comprising wave-trap meanscomprising quarter wavelength sections of high-freqnency transmissionlines for isolatin'gI-y spacing alternate radiators from, said support.

6 An nltra-high freguency broadband antenna system 9; an, energytransducer comprising a conductive suprz t ins mas fir t bu ar. ua -w ea ia es 4% ewn-a tached to said mast by means of a conductive disc atthe endof said radiator distal the base of said mast, a second tubularquarter-wave radiator, a third tubular isolating cylinder concentricwith said second radiator, said second radiator being attached to saidmast by means of a conductive disc at the similar end thereof throughsaid third cylinder, and transmission line means connecting saidradiators to such transducer.

7. An ultra-high frequency broadband antenna system for anenergytransducer comprising a conductive supporting mast and aplurality. of spaced antenna arrays mounted on said mast in spacedrelation, each array comprising a first tubular quarter-wave radiatorattached to said mast by means of a conductive disc at the end of saidradiator distal the base-ofsaid'mast, a second tubular quarter-waveradiator, a third tubular isolating cylinder concentric with said secondradiator, said second radiator being attached to. said mast by,mean sof: a conductive disc at the similar end thereof throughsaid thirdcylinder, and transmission line means connecting said radiators to suchtransducer.

References Cited in the file of this patent UNITED TAT S, PATENTS

